(19)
(11) EP 2 101 252 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
06.01.2010 Bulletin 2010/01

(43) Date of publication A2:
16.09.2009 Bulletin 2009/38

(21) Application number: 09154710.9

(22) Date of filing: 10.03.2009
(51) International Patent Classification (IPC): 
G06F 3/042(2006.01)
 G02B 6/00(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR
Designated Extension States:
AL BA RS

(30) Priority: 10.03.2008 JP 2008059581

(71) Applicant: Nitto Denko Corporation
Ibaraki-shi, Osaka 567-8680 (JP)

(72) Inventor:
  • Noriyuki, Juni
    Ibaraki-shi Osaka 567-8680 (JP)

(74) Representative: Skuhra, Udo 
Reinhard, Skuhra, Weise & Partner GbR Patent- und Rechtsanwälte Friedrichstraße 31
80801 München
80801 München (DE)

   


(54) Optical waveguide for touch panel and touch panel using the same


(57) An optical waveguide for a touch panel in which the intensity of light beams emitted from light-emitting portions of a plurality of light-emitting cores in the form of branches is substantially uniform independently of the branch position of the light-emitting cores, and a touch panel using the same. An optical waveguide for a touch panel is provided in which a plurality of light-emitting cores 33 are formed by dividing a tip portion of a single original core into branches. A portion extending from a basal portion 32b of the original core to a branch point 32c at which the division into the branches serving as the light-emitting cores 33 starts is an isosceles triangular portion 32 gradually widened from the basal portion 32b into the shape of an isosceles triangle. The isosceles triangle has a taper angle θ in the range greater than 0 degrees and less than 15 degrees.













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